A refrigerant compressor including discharge gas muffling means formed within the outer housing means by first and second wall means which cooperate with the bottom of the outer housing means to provide first and second chambers. The first chamber is connected by an inlet port to the compression mechanism for receiving discharge gas therefrom and a discharge port is provided from the second chamber to communicate the discharge gas to the discharge line of a refrigeration system. Divider walls within the first and second chambers are provided with restricted openings so as to provide restriction passages and expansion chamber muffling regions within the first and second chambers to effectively muffle noises emanating from the discharge gas passing from the compression mechanism to the discharge line outside of the compressor. In a modification, a third chamber may be added between the oil sump and discharge gas muffling chambers and a vacuum is pulled in the third chamber to materially reduce heat transfer much like a vacuum bottle does. A lubricant sump may be provided within the outer housing means above the second wall so as to reduce vibration and the emanation of noise from the discharge gas muffling means.